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A stimulus is anything that can trigger a physical or behavioral change. The plural of stimulus is stimuli.

Stimuli can be external or internal.

An example of external stimuli:

  • Your body responding to a medicine

An example of internal stimuli:

  • Your vital signs changing due to a change in the body

Stimuli include:

  • Irritants
  • Sights
  • Smells
  • Sounds
  • Temperature changes

Update Date 1/31/2015